KR102436923B1 - Block copolymer containing photo-sensitive moiety - Google Patents

Abstract

The present application may provide block copolymers and uses thereof. The present application may provide block copolymers and uses thereof. The block copolymer of the present application has excellent self-assembly properties or phase-separation properties, and at the same time has a property to change the self-assembled structure once formed, or to provide a block copolymer capable of forming a pattern of phase-separated structures in a polymer film. can

Description

Block copolymer including a photosensitive group {BLOCK COPOLYMER CONTAINING PHOTO-SENSITIVE MOIETY}

This application relates to a block copolymer including a photosensitive group.

The block copolymer has a molecular structure in which polymer blocks having different chemical structures are connected through covalent bonds. The block copolymer may form a periodically arranged structure such as a sphere, a cylinder, a gyroid, or a lamella by phase separation. The size of the domains of the structure formed by the self-assembly phenomenon of the block copolymer can be controlled in a wide range, and various types of structures can be fabricated, so that various next-generation nanometers such as high-density magnetic storage media, nanowire fabrication, quantum dots or metal dots, etc. It can be applied to device, magnetic recording medium, pattern formation by lithography, or the like.

The present application provides block copolymers and uses thereof.

This application relates to block copolymers. In the present application, the term block copolymer refers to a copolymer in which two different polymer segments are connected by a covalent bond.

In the present application, that any two types of polymer segments are the same is a case corresponding to any one of the following three cases. First, (1) when the types of monomer units included as main components of any two types of polymer segments are identical to each other, or (2) the types of monomer units included in any two types of polymer segments are 50% or more, 55% or more, 60% or more % or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, or 90% or more are common, and the deviation of the weight ratio of the common monomer unit of each polymer segment is within 30%, within 25% , within 20%, within 20%, within 15%, within 10%, or within 5%, both polymer segments may be treated as the same. It may be appropriate that the ratio of the monomer units common to the above is satisfied for both polymer segment modes. For example, when one polymer segment 1 has monomer units of A, B, C, D and F and the other polymer segment 2 has monomer units of D, F, G and H, in polymer segments 1 and 2, The common monomer units are D and F. From the standpoint of polymer segment 1, since two of the total 5 types of monomers are common, the common ratio is 40% (=100×2/5), but from the standpoint of polymer segment 2, the ratio is 50% (=100×2/5). Therefore, in this case, since the common ratio is 50% or more only in the polymer segment 2, it can be recognized that the two polymer segments are not identical. Meanwhile, in the above, the deviation of the weight ratio of the common monomer is a percentage of a value obtained by subtracting the small weight ratio from the large weight ratio divided by the small weight ratio. For example, in the above case, the weight ratio of D monomer units of segment 1 is about 40% based on 100% of the total weight ratio of all monomer units of segment 1, and the weight ratio of D monomer units of segment 2 is the total weight ratio of segment 2 If it is about 30% based on 100% of the total weight ratio of the monomer units, the weight ratio deviation may be about 33% (=100×(40-30)/30). If there are two or more common monomer units in the two segments, in order to be called the same segment, if the weight ratio deviation within 30% is satisfied for all common monomers or is satisfied for the monomer units that are the main components, it is a common monomer. can be considered

In another example, even if the deviation of solubility parameters of any two segments is within 30%, within 25%, within 20%, within 20%, within 15%, within 10%, or within 5%, both segments are the same can be considered as The deviation is the percentage of the value obtained by subtracting the small solubility parameter from the large solubility parameter divided by the small weight ratio, as in the case of the deviation of the weight ratio.

Each polymer segment recognized as the same by the above criteria may be a different type of polymer (for example, one segment is in the form of a block copolymer and the other segment is in the form of a random copolymer), It may suitably be a polymer of the same type.

In the present application, if only one of the three criteria is satisfied, it may be considered the same. For example, even if the deviation of the solubility parameter exceeds 30%, if the ratio of the common monomer is 50% or more and the deviation of the weight ratio is 30% or less, it may be the same segment, and vice versa. Conversely, a case in which all three criteria are not satisfied may be regarded as different segments.

In the present specification, that a component is included as a main component in an object means that the weight ratio of the included component is 55% or more, 60% or more, 65% or more, 70% or more, 75% or more based on the total weight of the object. , 80% or more, 85% or more, or 90% or more, and in this case, the upper limit of the ratio is not particularly limited, and may be, for example, about 100%. For example, that component A is included as a main component in component B is when the weight of component A included in component B is within the above range based on the total weight of component B.

The block copolymer of the present application includes at least a first polymer segment, a second polymer segment, and a third polymer segment. The three segments may be the same as or different from each other, but the case where all three segments are the same is not included. In one example, the three polymer segments may have a star-like structure in which they are covalently bonded while being shared at one connection point. Such block copolymers are also known in the art as so-called miktoarm block copolymers. The block copolymer of the present application may have an additional polymer segment as long as it includes at least the three segments. In one example, the polymer segments of the block copolymer of the present application may be 3 to 10, 3 to 8, 3 to 6, 3 or 4.

In the block copolymer, at least one polymer segment of the three polymer segments may be connected to the connection point by a so-called cleavable linker. In the present application, the cleavable linker refers to a linker that can be cleaved by an external action such as application of heat or irradiation of light. A variety of such linkers are known.

The present applicant has confirmed that the self-assembled structure can be changed after forming the self-assembled structure as described below by connecting at least one of the polymer segments with a cleavable linker in the block copolymer having the above-described structure. . For example, without being limited by theory, when the cleavable linker is cleaved through an external action after applying a block copolymer including three segments to form a self-assembled structure, the cleaved segment and the remaining block It is believed that the phase-separated structure is altered by the formation of a blend of copolymers and a change in the curvature at the interface of the separated phases in the phase-separated structure by the blend formed.

In particular, the Applicant discloses that at least one of the three polymer segments, that is, the first to third polymer segments, contains a vinyl pyridine unit, so that in particular, a block copolymer in which switching between a sphere structure and a cylinder structure is efficiently obtained can be obtained. It was confirmed that it is possible. In particular, the block copolymer of the above structure may be a block copolymer that forms a sphere structure in a state in which all three segments are connected, and implements a cylinder structure when the cleavable linker is separated. The segment including the vinyl pyridine unit may include the vinyl pyridine unit as a main component.

In order to more effectively achieve the above action, any one of the first to third polymer segments in the block copolymer may be different from the other two polymer segments. In one example, in the block copolymer, two polymer segments among the first to third polymer segments may be identical to each other, and the other polymer segment may be different from the two polymer segments. In this structure, the segment connected by the cleavable linker may be any one of the two polymer segments identical to each other. In this case, the segment cleaved in the blend formed by cleavage is miscible with any one segment of the segments of the remaining block copolymer implementing the phase-separated structure, and is not miscible with the other segments, and the phase-separated structure of the new structure is can be implemented.

The specific kind of each segment of the block copolymer is not particularly limited. For example, each of the first to third polymer segments includes a polyvinylpyrrolidone segment, a polylactic acid segment, a polyvinylpyridine segment, polystyrene or polytrimethylsilylstyrene, such as polystyrene (polystyrene). ) segment, a polyalkylene oxide segment such as polyethylene oxide, a poly butadiene segment, a poly isoprene segment, or a polyolefin segment such as polyethylene or polymethyl methacrylate, etc. Each of the poly(alkyl (meth)acrylate) segments may be selected so as to satisfy the above conditions.

In one example, a polymer segment different from the two polymer segments may be a polymer segment including the vinyl pyridine unit. Also, in this case, two polymer segments different from the polymer segment including the vinyl pyridine unit may each include a styrene unit, and the styrene unit may be included as a main component.

In the present application, the type of the cleavable linker connecting the polymer segment is not particularly limited, and a known cleavable linker may be applied. For example, the linker may be a linker including a 2-nitrobenzyl group, a coumarinyl group, a pyrenylalkyl group, etc. as a photocleavable linker, which is known. Linkers of this kind are known in various ways, and a method of connecting segments by applying such a linker is also known. In the present application, an appropriate linker may be selected from among these known linkers and used without limitation.

The number average molecular weight (Mn) of the block copolymer may be, for example, in the range of 1000 to 1000000. In the present specification, the term number average molecular weight is a value converted to standard polystyrene measured using a gel permeation chromatograph (GPC), and the term molecular weight in this specification means a number average molecular weight unless otherwise specified. In another example, the molecular weight (Mn) may be, for example, 5000 or more, 10000 or more, 50000 or more, 100000 or more, 300000 or more, 400000 or more, or 500000 or more. In another example, the molecular weight (Mn) may be about 900000 or less, 800000 or less, or 700000 or less. The block copolymer may have a polydispersity (Mw/Mn) within the range of 1.01 to 2. The degree of dispersion may be greater than or equal to about 1.05 or greater than or equal to about 1.1 in another example. The dispersion degree may be about 1.5 or less in another example.

In this range, the block copolymer may exhibit appropriate self-assembly properties. The number average molecular weight of the block copolymer may be adjusted in consideration of a desired self-assembled structure and the like.

When the block copolymer includes at least the first to third segments, the proportion of each segment in the block copolymer is not particularly limited, and may be appropriately selected in consideration of desired self-assembly characteristics. For example, as described above, when any two of the first to third segments are the same segment and the other segment is a different segment, the ratio of the one different segment in the block copolymer is 10 mol% to 90 mol%. % may be within the range.

A method of preparing the block copolymer of the present application is not particularly limited, and a known method may be applied.

For example, the block copolymer may be prepared by CLP (Controlled/Living Polymerization) method using monomers forming each segment. For example, anionic polymerization synthesized in the presence of an inorganic acid salt such as an alkali metal or alkaline earth metal salt using an organic rare earth metal complex as a polymerization initiator or an organic alkali metal compound as a polymerization initiator, an organic alkali metal compound polymerization Anionic polymerization method using an initiator and synthesizing in the presence of an organoaluminum compound, atom transfer radical polymerization (ATRP) using an atom transfer radical polymerization agent as a polymerization control agent, atom transfer radical polymerization method using an atom transfer radical polymerization agent as a polymerization control agent ARGET (Activators Regenerated by Electron Transfer) atom transfer radical polymerization method (ATRP), ICAR (Initiators for continuous activator regeneration) atom transfer radical polymerization method (ATRP), reversible addition of inorganic reducing agent- There is a polymerization method by reversible addition-cleavage chain transfer (RAFT) using a cleavage chain transfer agent or a method using an organic tellurium compound as an initiator, and an appropriate method may be selected and applied among these methods.

In this process, an initiator, a chain transfer material, or a block copolymer to which a protecting group is applied to form a star structure may be applied, and a known process for introducing a cleavable linker may also be performed.

The present application also relates to a polymer membrane comprising the block copolymer. The polymer film may be used for various purposes, for example, it may be used in various electronic or electronic devices, a process of forming the pattern or a recording medium such as a magnetic storage recording medium, a flash memory, or a biosensor.

In one example, the block copolymer in the polymer film may implement a periodic structure including a sphere, a cylinder, a gyroid, or a lamella through self-assembly. .

For example, in the block copolymer, other segments in the first or second segment or another segment covalently bonded thereto may form a regular structure such as a lamellar shape or a cylindrical shape.

In one example, the phase-separated structure in the block copolymer may be a structure in which two or more of the above-described structures exist together. Such a structure may be formed through the process of cutting the cleavable linker after once forming a self-assembled structure by applying the block copolymer of the present application as described above. Accordingly, in this case, in the polymer film, one segment among the first to third polymer segments may be cleaved and mixed with the block copolymer including two other segments.

In one example, a sphere structure is implemented in a state or part in which all of the first to third segments are connected in the polymer membrane, and one segment is cut from among the first to third polymer segments and the other two segments A cylinder structure may be implemented in a mixed state or part with a block copolymer comprising a.

The polymer segment mixed with the block copolymer including the other two segments in the cleaved state may be a segment including a styrene unit.

The present application also relates to a method of forming a polymer film using the block copolymer. The method may include forming a polymer film including the block copolymer on a substrate in a self-assembled state. For example, the method may include forming a layer of the block copolymer or a coating solution diluted therein in an appropriate solvent on the substrate by application or the like, and if necessary, aging or heat treatment of the layer.

The aging or heat treatment, for example, may be performed based on the phase transition temperature or glass transition temperature of the block copolymer, for example, may be performed at a temperature above the glass transition temperature or the phase transition temperature. The time period for which this heat treatment is performed is not particularly limited and, for example, may be performed within the range of about 1 minute to 72 hours, but this may be changed as necessary. In addition, the heat treatment temperature of the polymer thin film may be, for example, about 100 °C to 250 °C, which may be changed in consideration of the block copolymer used.

In another example, the formed layer may be solvent-aged for about 1 minute to 72 hours in a non-polar solvent and/or a polar solvent at room temperature.

In one example, the method of forming the polymer film may include: implementing a first phase separation structure using the above-described block copolymer; and cleaving the cleavable linker of the block copolymer implementing the first phase-separated structure, and as described above, a second phase-separated structure different from the first phase-separated structure is formed by the cleaving step. It may be formed in a polymer film. In this case, the method for cleaving the cleavable linker is not particularly limited, and an appropriate method may be selected in consideration of the type of the applied linker.

In one example, the first phase-separation structure may be a sphere structure, and the second phase-separation structure may have a cylinder structure.

Such cutting may be performed entirely on the polymer film, or may be performed only on a part through masking or the like. In addition, each of the first and second phase separation structures may be selected from the group consisting of a sphere, a cylinder, a gyroid, and a lamella structure.

The present application also relates to a method of forming a pattern. The method is, for example, a process of selectively removing any one segment of the block copolymer from a laminate having a substrate and the polymer film formed on the surface of the substrate and including the self-assembled block copolymer may include The method may be a method of forming a pattern on the substrate. For example, the method may include forming a polymer film including the block copolymer on a substrate, and etching the substrate after selectively removing any one or more blocks of the block copolymer present in the film. . In this way, the formation of, for example, nanoscale micropatterns is possible. In addition, according to the shape of the block copolymer in the polymer film, various types of patterns such as nanorods or nanoholes may be formed through the above method. If necessary, the block copolymer and other copolymers or homopolymers may be mixed to form a pattern. The type of the substrate applied in this way is not particularly limited, and may be selected as necessary, for example, silicon oxide or the like may be applied.

For example, the method can form a nanoscale pattern of silicon oxide exhibiting a high aspect ratio. For example, after forming the polymer film on silicon oxide and selectively removing any one block of the block copolymer in a state in which the block copolymer in the polymer film forms a predetermined structure, silicon oxide is removed in various ways, for example , reactive ion etching, etc. can be etched to implement various shapes including patterns of nanorods or nanoholes.

The method of selectively removing any one segment of the block copolymer in the above method is not particularly limited, and for example, a method of removing a relatively soft block by irradiating an appropriate electromagnetic wave to the polymer film, for example, ultraviolet rays, etc. Can be used. In this case, the UV irradiation conditions are determined according to the type of block of the block copolymer, and for example, it may be performed by irradiating UV rays with a wavelength of about 254 nm for 1 minute to 60 minutes.

In addition, a step of further removing the segment decomposed by ultraviolet light may be performed by treating the polymer film with an acid or the like following ultraviolet irradiation.

In addition, the step of etching the substrate using the polymer film from which the block has been selectively removed as a mask is not particularly limited, and for example, it can be performed through a reactive ion etching step using CF4/Ar ions, etc., followed by this process The step of removing the polymer film from the substrate by oxygen plasma treatment or the like may also be performed.

The present application may provide block copolymers and uses thereof. The block copolymer of the present application has excellent self-assembly properties or phase-separation properties, and at the same time has a property to change the self-assembled structure once formed, or to provide a block copolymer capable of forming a pattern of phase-separated structures in a polymer film. can

1 to 10 are analysis results for the compound or polymer prepared in Preparation Example.
11 is a GPC curve for the polymer (D) before and after UV irradiation in Example 1.
12 is a TEM image of the polymer (D) of Example 2 before UV irradiation.
13 is a TEM image of a sample after UV irradiation with respect to the polymer (D) of Example 2, and the small image in the upper left is a TEM image taken in the vertical direction.
14 is a SAXS graph of a sample before UV irradiation for the polymer (D) of Example 2. FIG.
15 is a SAXS graph of a sample after UV irradiation for the polymer (D) of Example 2. FIG.
16 is an AFM image of a cross-section of a thin film sample before UV irradiation for polymer (D) in Example 3. FIG.
17 is an AFM image of a thin film sample after UV irradiation with respect to the polymer (D) in Example 3.
FIG. 18 is an SEM image of a thin film sample transferred to metal nanoparticles before UV irradiation with respect to the polymer (D) in Example 4. FIG.
19 is an SEM image of a thin film sample transferred to metal nanoparticles after UV irradiation with respect to the polymer (D) in Example 4.

Hereinafter, the present application will be described in more detail through Examples, but the scope of the present application is not limited by the Examples presented below.

1. NMR measurement

NMR analysis was performed at room temperature using an NMR spectrometer including a Varian Unity Inova (500 MHz) spectrometer with a triple resonance 5 mm probe. The analyte material was diluted to a concentration of about 10 mg/ml in a solvent for NMR measurement (CDCl ₃ ), and chemical shift was expressed in ppm.

<Applicable Abbreviations>

br = broad signal, s = singlet, d = doublet, dd = double doublet, t = triplet, dt = double triplet, q = quartet, p = quintet, m = multiplet.

2. Gel Permeation Chromatograph (GPC)

The number average molecular weight (Mn) and molecular weight distribution were measured using gel permeation chromatography (GPC). In a 5 mL vial, put the analyte, such as the block copolymer or macro initiator of Examples or Comparative Examples, and dilute it in THF (tetrahydro furan) to a concentration of about 1 mg/mL. After that, the standard sample for calibration and the sample to be analyzed were filtered through a syringe filter (pore size: 0.45 μm) and then measured. As the analysis program, ChemStation of Agilent Technologies was used, and the weight average molecular weight (Mw) and number average molecular weight (Mn) were obtained by comparing the elution time of the sample with the calibration curve, and the molecular weight distribution (PDI) was obtained by the ratio (Mw/Mn). ) was calculated. The measurement conditions of GPC are as follows.

<GPC measurement conditions>

Instrument: 1200 series from Agilent technologies

Column: 2 PLgel mixed B from Polymer laboratories

Solvent: THF

Column temperature: 35°C

Sample concentration: 1mg/mL, 200uL injection

Standard sample: polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

Preparation Example 1.

A compound of Formula 1 (5-(4-bromobutoxy)-2-nitrophenyl)methanol) was prepared in the following manner. After dissolving 5 g (29.6 mmol) of 5-hydroxy-1-nitrobenzyl alcohol in 200 mL of acetonitrile, stirring at 0° C., sodium hydride (sodium hydride, 2.16 g, 90 mmol) aqueous solution was added. The obtained yellow precipitate was filtered and dissolved in DMF (Dimethylformamide) (150 mL). After complete dissolution, dibromobutane (7.03 g, 32.56 mmol) was slowly added at room temperature. After reacting for 12 hours, distilled water was poured to terminate the reaction, followed by extraction with ethyl acetate. Purification by column chromatography gave the compound of Formula 1 below. 1 is an analysis result for the compound.

[Formula 1]

<NMR analysis result>

¹ H-NMR (400 MHz, CDCl ₃ ): d8.06(d, 1H); d7.12(s, 1H); d6.78(d, 1H); d4.88(s, 2H); d4.02(t, 2H); d3.32(t, 2H); d3.20(s, 1H); d1.98(p, 2H); d1.90 (p, 2H).

Preparation Example 2.

A compound of Formula 2 (5-(4-azidobutoxy)-2-nitrophenyl)methanol) was prepared in the following manner. The compound of Formula 1 of Preparation Example 1 (8.5 g, 27.9 mmol) and sodium azide (2.36 g, 36.3 mmol) were dissolved in a mixed solvent (6:1) of acetone and distilled water, and at 65° C. in a nitrogen atmosphere. The target was obtained by reflux. Attached Figure 2 is an analysis result for the compound.

[Formula 2]

<NMR analysis result>

¹ H-NMR (400 MHz, CDCl ₃ ): d8.06(d, 1H); d7.12(s, 1H); d6.78(d, 1H); d5.52(s, 2H); d4.02(t, 2H); d3.32(t, 2H); d3.20(s, 1H); d1.98(p, 2H); d1.90 (p, 2H).

Preparation Example 3.

A compound of Formula 3 (5-(4-azidobutoxy)-2-nitrophenyl 2-bromo-2-methylpropanoate) was prepared in the following manner. Dissolving the compound of Formula 2 (7.19 g, 27.0 mmol) of Preparation Example 2 in THF (Tetrahydrofuran), while stirring at 40 ° C with triethylamine (3.24 g, 32.0 mmol) in a nitrogen atmosphere, 2-bromo-2 -Methylpropanoyl bromide (2-bromo-2-methylpropanoyl bromide) (7.45 g, 32.4 mmol) was added. The salt generated during the reaction was filtered off and purified by column chromatography to obtain a compound of Formula 3 below. 3 is an analysis result for the compound.

[Formula 3]

<NMR analysis result>

¹ H-NMR (400 MHz, CDCl ₃ ): d8.06(d, 1H); d7.12(s, 1H); d6.78(d 1H); d5.52(s, 2H); d4.02(t, 2H); d3.32(t, 2H); d1.99(s, 6H); d1.98(p, 2H); d1.90 (p, 2H).

Preparation Example 4.

A compound of Formula 4 (1-bromo-4-(1-phenylvinyl)benzene) was prepared in the following manner. Methyl triphenylphosphonium bromide (7.2 g, 20 mmol) and potassium tert-butoxide (2.3 g, 20 mmol) were put in THF (Tetrahydrofuran) (50 mL), and at room temperature THF (Tetrahydrofuran) (35 mL) in which p-bromobenzophenone (3.4 g, 17 mmol) was dissolved was slowly added thereto while stirring, and the mixture was reacted for 3 hours. After the reaction, a saturated aqueous solution of ammonium chloride was added to terminate the reaction, and extraction was performed with diethyl ether to obtain a compound of formula 4 as a product. 4 is an analysis result for the compound.

[Formula 4]

<NMR analysis result>

¹ H-NMR (400 MHz, CDCl ₃ ): d7.33 (d, 2H); d7.19(d, 5H); d7.05(d, 2H); d5.32 (d, 2H).

Preparation 5.

A compound of Formula 5 (tert-butyldimethyl((4-(1-phenylvinyl)phenyl)ethynyl)silane) was prepared in the following manner. After completely dissolving the compound of Formula 4 (3.89 g, 15 mmol) in Preparation Example 4 in piperidine (50 mL), tert-butyldimethylsilylacetylene (2.53 g, 18 mmol) was added. added. Then, after reacting at 50 °C for 24 hours, filtered, extracted with hexane, and purified by column chromatography to obtain the compound of formula 5. 5 is an analysis result for the compound.

[Formula 5]

<NMR analysis result>

¹ H-NMR (400 MHz, CDCl ₃ ): d7.33 (d, 2H); d7.19(d, 5H); d7.05(d, 2H); d5.32(d, 2H); d1.03(s, 9H); d0.22 (d, 6H).

Preparation 6.

A polymer (A) of the following formula (6) was synthesized. Using the compound of Formula 3 (50 mg) of Preparation Example 3 as an initiator, styrene (6 mL) and copper (I) bromide (18 mg), and PMDETA (N,N,N', The reaction solution mixed with N",N"-pentamethyldiethylenetriamine, 24 μL) was freeze-thawed 3 times and polymerized while stirring at 90 °C under a nitrogen atmosphere. The polymer solution was passed through an alumina column to remove the catalyst, and precipitated in methanol to obtain a powder of the polymer (A). The number average molecular weight (Mn) of the polymer (A) was about 12000, and the molecular weight distribution (Mw/Mn) was about 1.18. 6 shows the measurement results of the polymer (A).

[Formula 6]

Preparation 7.

A polymer (B) of the following formula (7) was synthesized. Lithium chloride (0.3 g) and THF (80 mL) were added to a reactor in an argon atmosphere, and stirred at -78 °C to sufficiently dissolve. Then, 86 μL of a 1.2M sec-butyl lithium solution was added, and purified styrene (3.0 g) was added thereto. After sufficient stirring for about 1 hour, the compound of Formula 5 of Preparation Example 5 was added. Subsequently, 2-vinyl pyridine (2VP) (1.25 g) was added, and after stirring for about 1 hour, the reaction was terminated using 2-propanol to obtain a polymer (B). . The number average molecular weight (Mn) of the polymer (B) was about 45000, and the molecular weight distribution (Mw/Mn) was about 1.20. Also, the mass fraction of polystyrene segments in polymer (B) was about 72%. 7 is a GPC measurement result for the polymer (B).

[Formula 7]

Preparation 8.

A polymer (C) of the following formula (8) from which TBDMS, a protecting group, has been removed from the polymer (B) of the formula (7) was synthesized. After the polymer (B) of Preparation Example 7 was completely dissolved in THF, it was sufficiently degassed with nitrogen, and 10 mL of a tetrabutylammonium fluoride solution (1.0M in THF) was added and stirred at room temperature for 12 hours. . After the reaction, THF was removed, and the solvent was changed to chloroform and purified through column chromatography. As shown in FIG. 8 , it was confirmed that the peak of d=0.2 corresponding to Si(CH ₃ ) included in the protecting group in the polymer (B) disappeared through the reaction.

[Formula 8]

Preparation 9.

By coupling the polymer (A) and the polymer (C), a miktoarm block copolymer (polymer (D)) having three polymer segment arms was synthesized. Polymer (A) 0.1 g (1.2 eq.) and Polymer (C) 0.25 g (1.0 eq.) were sufficiently dissolved in 5 mL of THF, followed by degassing with nitrogen. While flowing nitrogen, after adding PMDETA (N,N,N',N",N"-pentamethyldiethylenetriamine, 24 mL) and copper(I) bromide (18 mg) in order, the reactor After sealing and stirring at room temperature for 2 days, the polymer (A) remaining was removed through purification to obtain a polymer (D). The number average molecular weight (Mn) of the polymer (D) was about 60000, and the molecular weight distribution (Mw/Mn) was about 1.20. Also, the mass fraction of polystyrene segments in polymer (D) was about 80%. 9 is a GPC measurement result for the polymer (D), and FIG. 10 is a comparison result of NMR before and after the reaction.

[Formula 9]

Example 1.

Polymer (D) 10 mg was dissolved in THF (5 mL), coated on a glass substrate, and then irradiated with ultraviolet rays having a wavelength of about 365 nm. After irradiation with ultraviolet light for 1 hour, it was confirmed that the photo-cleavable linker of the polymer (D) was decomposed and completely decomposed into the derivative of the polymer (A) and the derivative of the polymer (C). In addition, as a result of analyzing the decomposed polymers by GPC, peaks corresponding to the derivative of the polymer (A) and the derivative of the polymer (C) were confirmed ( FIG. 11 ).

Example 2.

Two samples were prepared by dissolving 10 mg of polymer (D) in THF (5 mL) and solvent drop casting, one sample was not irradiated with ultraviolet rays, and the other sample was irradiated with ultraviolet rays having a wavelength of about 365 nm. Then, the two samples were each annealed at about 230 °C for about 3 days, and a TEM (transmission electron microscopy) specimen was prepared through microtoming, and the TEM was confirmed using the above, and SAXS (small angle X) for the two samples. -ray scattering) analysis was also performed. As a result of the confirmation, in the case of the sample not irradiated with ultraviolet rays among the two samples, a fine phase-separated structure of the cylinder morphology was observed. Results for the measurement results are shown in FIGS. 12 to 15 .

Example 3.

The polymer (D) was spin-coated on a silicon substrate to prepare a polymer thin film sample with a thickness of about 60 nm. Then, a part of the sample was not irradiated with ultraviolet rays, and the other part was irradiated with ultraviolet rays having a wavelength of about 365 nm. Then, the sample was annealed, and as a result of observation by AFM (Atomic Force Microscopy), a fine phase-separation structure of spheres was confirmed in the portion not irradiated with ultraviolet rays, and a fine-phase-separation structure of cylinders oriented horizontally to the substrate in the irradiated portion was confirmed. The measurement results are shown in FIGS. 16 and 17 .

Example 4.

A trench structure was formed on a silicon wafer substrate in the following manner. A layer of SiO ₂ was formed to a thickness of about 200 nm on the substrate by a known deposition method. Then, BARC (Bottom Anti-reflective coating) is coated on the SiO ₂ layer to a thickness of about 60 nm, and a PR (photoresist) layer (for KrF, positive-tone resist layer) is applied thereon to a thickness of about 400 nm. coated. Then, the PR layer was patterned by a KrF stepper exposure method. Then, by using the patterned PR layer as a mask by RIE (Reactive Ion Etching) method, the BARC layer and the SiO ₂ layer below it were etched, and the BARC layer and the residues of the PR layer were removed to form a mesa structure. The spacing (D) between the mesa structures formed in this way was about 150 nm, the height (H) was about 50 nm, and the width (W) of each mesa structure was about 150 nm.

A polymer film sample having a thickness of about 60 nm was prepared by spin-coating the polymer (D) on the mesa structure (trench structure) of the substrate formed in the above manner. Then, a part of the sample was not irradiated with ultraviolet rays, and the other part was annealed after irradiating ultraviolet rays with a wavelength of about 365 nm. A thin film having two microphases was immersed in an acidic solution (HCl solution, 1%) in which a metal salt (Na2PtCL4) was dissolved for 3 hours. Subsequently, two nanostructures of platinum nanoparticles and platinum nanowires were obtained by removing the polymer with O2 RIE and simultaneously reducing the metal salt. The results of SEM (Scanning Electron Microscopy) are shown in FIGS. 18 and 19 .

Claims (15)

a first polymer segment, a second polymer segment and a third polymer segment;
It has a star structure in which the three polymer segments are covalently bonded while being shared at one connection point,
The linker connecting at least one polymer segment of the three polymer segments to the connection point is a cleavable linker,
At least one of the first to third polymer segments comprises a vinyl pyridine unit. According to claim 1, wherein two polymer segments of the first to third polymer segments are identical to each other, the other polymer segment is different from the two polymer segments, and the polymer segments different from the two polymer segments are vinyl. A block copolymer comprising pyridine units. The block air according to claim 2, wherein, among the first to third polymer segments, identical to each other, at least 50% of the constituent monomer units are identical to each other, and the difference in the segment of the same monomer is within 20% by weight. coalescence. The block copolymer according to claim 2, wherein, among the first to third polymer segments, the same segment has a solubility parameter within 10% of each polymer segment. The block copolymer according to claim 2, wherein one of the two segments identical to each other among the first to third polymer segments is connected to the connection point by a cleavable linker. The block copolymer according to claim 1, wherein one segment of the first to third polymer segments includes a vinyl pyridine unit, and the other two segments include a styrene unit. The block copolymer according to claim 1, wherein the cleavable segment includes a 2-nitrobenzyl group, a coumarinyl group, and a pyrenylalkyl group. The block copolymer according to claim 1, wherein the number average molecular weight is in the range of 1,000 to 1,000,000. The block copolymer according to claim 1, wherein the molecular weight distribution is in the range of 1.01 to 2. A polymer membrane comprising the self-assembled block copolymer of claim 1. The polymer membrane according to claim 10, wherein two or more phase-separated structures selected from the group consisting of a sphere, a cylinder, a gyroid, and a lamella structure simultaneously exist. The polymer film according to claim 10, wherein one of the first to third polymer segments of the block copolymer is mixed with the block copolymer including the other two segments in a cleaved state. The polymer membrane according to claim 12, wherein the polymer segment in the cleaved state contains styrene units. A method of forming a polymer film comprising the self-assembled block copolymer of claim 1 on a substrate, the method comprising:
Implementing a first phase-separated structure using the block copolymer of claim 1; and cutting the cleavable linker of the block copolymer implementing the first phase separation structure,
A method of forming a polymer film in which a second phase-separation structure different from the first phase-separation structure is formed in the polymer film after the cutting step. The method of claim 14 , wherein each of the first phase-separated structures includes a sphere structure, and the second phase-separated structure includes a cylinder structure.

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